DPlan - Model Options
In general, you should leave the following parameters at their default values:
The Z1 / Z1b option selects between a 4 minute or 5 minute fastest tissue compartment for the ZH-L models only. Most decompression modeling is done with the 1b ( 5 minute ) compartment. This has little effect, except in extremely short bounce dives.
RQ is Respiratory Quotient, and may be varied between 0.8 ( Shreiner’s medical value, conservative ) and 0.9 ( US Navy value for divers, liberal. ) It has very little effect. Unchecking RQ has the same effect as setting it to 1.00, and actually increases conservatism.
Disabling H2O Effects is useful when comparing results to older decompression programs that do not model alveolar water vapor effects, like Z-Planner. Unchecking H2O Effects has a slightly conservative effect, but for accuracy, you should leave it enabled. CO2 effects is similar.
Disabling He Effects causes the program to base its decompression schedules on Nitrogen M-values alone. Effectively, this causes Helium to on-gas at its own (faster) rate, but off-gas at the same rate as Nitrogen, which will have very a conservative effect on helium mixes, but no effect on non-helium mixes. Some decompression models do this by design, and some older softwares may do this also, although it makes little sense to me.
